Starter air valve systems configured for low speed motoring

ABSTRACT

A starter air valve (SAV) system includes a pressure actuated SAV actuator configured to be operatively connected to a SAV, a first pressure valve configured to selectively allow pressure from a pressure source to the SAV actuator when in fluid communication with the SAV actuator, and a second pressure valve configured to selectively allow pressure from the pressure source to the SAV actuator when in fluid communication with the SAV actuator. A manual override (MOR) valve selector is disposed between the first pressure valve, the second pressure valve, and the SAV actuator, the MOR valve selector configured to selectively fluidly connect the first pressure valve and the SAV actuator in a first position and to fluidly connect the second pressure valve and the SAV actuator in a second position.

BACKGROUND 1. Field

The present disclosure relates to turbomachine starter air valves, morespecifically to starter air valve systems for low speed motoring.

2. Description of Related Art

Turbomachine engines are becoming progressively smaller and operatehotter. Upon engine shut down, due to uneven rate of cooling at its topand bottom the bowed rotor phenomenon occurs. If start is attemptedduring this condition, blade rub occurs. One potential solution is tomotor the engine (to rotate the engine without turning it on) prior tostart in order to reverse the bow.

The engine should be motored within a narrow band of very low speeds inorder to cool down. This is, because at higher revolutions an engine rubwill occur, while dwelling at lower speeds than recommended, a resonanceleading to catastrophic failure develops. Motoring is done using airflow from the Auxiliary Power Unit (APU) to the engine starter which inturn rotates the engine. Given the above constraints, air flow must becontrolled by a valve to control the flow from the APU at starter valve.The problem with the current systems and the air valves that are beingused is that they are not designed to motor the engine at low speeds(e.g., an APU starter is inherently designed to speed the engine up tooperational speed).

Conventional methods and systems have generally been consideredsatisfactory for their intended purpose. However, there is still a needin the art for improved starter air valve systems. The presentdisclosure provides a solution for this need.

SUMMARY

In accordance with at least one aspect of this disclosure, a starter airvalve (SAV) system includes a pressure actuated SAV actuator configuredto be operatively connected to a SAV, a first pressure valve configuredto selectively allow pressure from a pressure source to the SAV actuatorwhen in fluid communication with the SAV actuator, and a second pressurevalve configured to selectively allow pressure from the pressure sourceto the SAV actuator when in fluid communication with the SAV actuator. Amanual override (MOR) valve selector is disposed between the firstpressure valve, the second pressure valve, and the SAV actuator, the MORvalve selector configured to selectively fluidly connect the firstpressure valve and the SAV actuator in a first position and to fluidlyconnect the second pressure valve and the SAV actuator in a secondposition.

In certain embodiments, at least one of the first pressure valve orsecond pressure valve can be a pulse-width modulation solenoid valveconfigured to provide a duty cycle of pressure from the pressure sourceto the SAV actuator when in fluid communication with the SAV actuator.The SAV can include at least one of a butterfly valve or an inline valvevalve or any other suitable valve.

The first pressure valve can be operatively connected to a firstcontroller to control the first pressure valve. The first controller canbe an engine computer, for example.

In certain embodiments, the second pressure valve can be operativelyconnected to a second controller to control the second pressure valve.The second controller can include a secondary power source configure tobe switched on when the MOR valve selector is in the second position.

The second controller can include a control module operatively connectedto the second pressure valve. The second controller can include a speedsensor operatively connected to the control module and configured tosense an engine speed for providing speed data to the control module.

In certain embodiments, the system can include a manual selector forindicating which position the MOR valve selector is in. For example, anormal start indication can correspond to the first position and a BRSMOR indication can correspond to the second position. The system caninclude the pressure source operatively connected to the first pressurevalve and the second pressure valve.

In accordance with at least one aspect of this disclosure, a starter airvalve (SAV) system includes a pressure actuated SAV actuator configuredto be operatively connected to a SAV and a first pressure valveconfigured to selectively allow pressure from a pressure source to theSAV actuator when in fluid communication with the SAV actuator. Thefirst pressure is a pulse-width modulation solenoid valve configured toprovide a duty cycle of pressure from the pressure source to the SAVactuator.

In accordance with at least one aspect of this disclosure, a methodincludes pulse width modulating a first pressure valve to provide a dutycycle of pressure to a starter air valve actuator based on an enginespeed to actuate a starter air valve (SAV) to motor an engine at apredetermined motoring speed. The method can include selecting a secondpressure valve to provide the duty cycle of pressure to SAV actuatorbased on the engine speed to actuate a starter air valve (SAV) to motoran engine at a predetermined motoring speed. Selecting the secondpressure valve can include using a manual override (MOR) valve selector.

These and other features of the systems and methods of the subjectdisclosure will become more readily apparent to those skilled in the artfrom the following detailed description taken in conjunction with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those skilled in the art to which the subject disclosureappertains will readily understand how to make and use the devices andmethods of the subject disclosure without undue experimentation,embodiments thereof will be described in detail herein below withreference to certain figures, wherein:

FIG. 1 is a schematic view of an embodiment of a system in accordancewith this disclosure, showing a manual override (MOR) valve selector ina first (e.g., normal operating) position; and

FIG. 2 is a schematic view of the system of FIG. 1, showing the MORvalve selector in a second (e.g., manual override) position.

DETAILED DESCRIPTION

Reference will now be made to the drawings wherein like referencenumerals identify similar structural features or aspects of the subjectdisclosure. For purposes of explanation and illustration, and notlimitation, an illustrative view of an embodiment of a system inaccordance with the disclosure is shown in FIG. 1 and is designatedgenerally by reference character 100. Other embodiments and/or aspectsof this disclosure are shown in FIG. 2. The systems and methodsdescribed herein can be used to allow controlled low speed enginemotoring and redundant starter air valve control.

Referring to FIGS. 1 and 2, a starter air valve (SAV) system 100 (e.g.,for an aircraft turbomachine) includes a pressure actuated SAV actuator101 configured to be operatively connected to a SAV 103. As shown, theSAV can include at least one of a butterfly valve or an inline valvevalve, for example, or any other suitable valve.

A first pressure valve 105 is configured to selectively allow pressurefrom a pressure source 107 to the SAV actuator 101 when in fluidcommunication with the SAV actuator 101. The system 100 can also includea second pressure valve 109 configured to selectively allow pressurefrom the pressure source 107 to the SAV actuator 101 when in fluidcommunication with the SAV actuator 101.

A manual override (MOR) valve selector 111 can be disposed between thefirst pressure valve 105, the second pressure valve 109, and the SAVactuator 101. The MOR valve selector 111 is configured to selectivelyfluidly connect the first pressure valve 105 and the SAV actuator 101 ina first position (e.g. as shown in FIG. 1) and to fluidly connect thesecond pressure valve 109 and the SAV actuator 101 in a second position(e.g., as shown in FIG. 2).

In certain embodiments, at least one of the first pressure valve 105 orsecond pressure valve 109 can be a pulse-width modulation solenoid valveconfigured to provide a duty cycle of pressure from the pressure source107 to the SAV actuator 101 when in fluid communication with the SAVactuator 101. In this regard, the first pressure valve 105 and/or secondpressure valve 109 can allow intermittent pressure of any suitableinterval and/or duty cycle of said intervals to reach the SAV actuator101 which ultimately gates the amount of flow allowed through the SAV103.

In certain embodiments, the first pressure valve 105 can be operativelyconnected to a first controller 113 to control the first pressure valve105. The first controller 113 can be an engine computer (e.g., an EEC),for example. The first controller 113 can also connect to and/orotherwise control the second pressure valve 109 in certain embodiments.The first controller 113 can be operatively associated with one or moresensors associated with an engine (e.g., speed sensors) to control thefirst pressure valve 105 and/or the second pressure valve 109.

In certain embodiments, the second pressure valve 109 can be operativelyconnected to a second controller 115 to control the second pressurevalve 109 in addition to or separate from the first controller 113. Thesecond controller 115 can include a secondary power source 117configured to be switched on when the MOR valve selector 111 is in thesecond position (e.g., as shown in FIG. 2). In certain embodiments, thesecond pressure valve 109 might be mounted in a remote location (e.g.,in an aircraft cockpit, on engine casing), for example, or any othersuitable location.

The second controller 115 can include a control module 119 operativelyconnected to the second pressure valve 109. The second controller 115can include a speed sensor 121 operatively connected to the controlmodule 119 and configured to sense an engine speed for providing speeddata to the control module 119, for example. The control module 119 canbe connected to any other suitable sensor. The second controller 115 canbe configured to pulse-width modulate the second pressure valve 109 toprovide a pulsed pressure signal to the SAV actuator 101 in the secondposition with the purpose of motoring the engine at a predetermined timefollowed by a full start.

In certain embodiments, the system 100 can include a manual selector 123for indicating which position the MOR valve selector 111 is in. Forexample, a normal start indication can correspond to the first position(e.g., as in FIG. 1) and a BRS MOR indication can correspond to thesecond position (e.g., as in FIG. 2).

The system 100 can include the pressure source 107 operatively connectedto the first pressure valve 105 and the second pressure valve 109. Incertain embodiments, the pressure source 107 supplied to the firstpressure valve 105 can be different from a pressure source providing apressure to be controlled by the SAV actuator.

In accordance with at least one aspect of this disclosure, a starter airvalve (SAV) system 100 includes a pressure actuated SAV actuator 101configured to be operatively connected to a SAV 103 and the firstpressure valve 105 that is a pulse-width modulation solenoid valveconfigured to provide a duty cycle of pressure from the pressure sourceto the SAV actuator 101, without a the MOR valve selector 111 and/or asecond pressure valve 109.

In accordance with at least one aspect of this disclosure, a methodincludes pulse width modulating a first pressure valve to provide a dutycycle of pressure to a starter air valve actuator based on an enginespeed to actuate a starter air valve (SAV) to motor an engine at apredetermined motoring speed. The method can include selecting a secondpressure valve to provide the duty cycle of pressure to SAV actuatorbased on the engine speed to actuate a starter air valve (SAV) to motoran engine at a predetermined motoring speed. Selecting the secondpressure valve can include using a manual override (MOR) valve selector.

Certain embodiments of the method do not take inputs from the enginecomputer in order to determine optimum motoring time. Certainembodiments include motoring the engine at a predetermined time intervalwhich can be derived based on the worst motoring condition for theparticular engine corresponding to maximum motor time.

As described above, during normal operation the engine completes amotoring sequence leading to start. The pressure valve solenoid is pulsewidth modulated by the first controller 113 (e.g., an EEC with an inputfrom the engine N2 sensor). The MOR valve selector 111 blocks (e.g.,mechanically) the duct connecting the MOR valve selector 111 to the SAVactuator 101. In certain embodiments, it also disengages the circuitswitching the power to the controller 115, for example.

During a failure condition, the MOR valve selector can be utilized. Theclosed loop control can be achieved with inputs from the speed sensor121 (e.g., mounted on the accessory gearbox crankshaft). Prior to start,a technician can set the system to BRS MOR position as shown in FIG. 2.This blocks the duct connecting first pressure valve 105 to the SAVactuator 101 and closes the circuit that switches power to thecontroller 115, for example. During the motoring sequence the secondpressure valve 109 can be pulse width modulated. To avoid human error,the motoring sequence can equal the maximum specified per therequirements for the particular engine after which the second pressurevalve 109 is commanded open by the second controller 115 (or firstcontroller 113) and full start sequence is completed.

In certain embodiments, the SAV can include a fitting allowing a user tomanually unstuck the SAV due to an obstruct by manually turning the SAV.In a condition where the SAV is stuck closed due to obstruction, thepressure source (i.e. APU, ground cart, etc.) and any functions that maylead to engine turning are switched off. The nacelle can be opened andthe SAV can be accessed via a fitting (e.g., on the butterfly shaft)that would allow a technician to turn the mechanism manually and unstuckthe SAV.

Embodiments as described above utilize a pulse-width capable solenoidcontrolled by a circuit card or other suitable controller with inputsfrom a speed sensor (e.g., mounted on the accessory gearbox crank pad).Certain embodiments also include a MOR valve selector. Embodiments solvethe problems of pressure valve solenoid electrical failure, pressurevalve solenoid-EEC link failure, pressure valve solenoid mechanicallybeing stuck closed or open, and sluggish SAV, for example. Embodimentsprevent over speeding during motoring and prevent a bowed rotor fromcausing rubbing.

As will be appreciated by those skilled in the art, aspects of thepresent disclosure may be embodied as a system, method or computerprogram product. Accordingly, aspects of the present invention may takethe form of an entirely hardware embodiment, an entirely softwareembodiment (including firmware, resident software, micro-code, etc.) oran embodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described above with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified herein.

The methods and systems of the present disclosure, as described aboveand shown in the drawings, provide for SAV systems with superiorproperties. While the apparatus and methods of the subject disclosurehave been shown and described with reference to embodiments, thoseskilled in the art will readily appreciate that changes and/ormodifications may be made thereto without departing from the spirit andscope of the subject disclosure.

What is claimed is:
 1. A method comprising, pulse width modulating afirst pressure valve to provide a duty cycle of pressure to a starterair valve actuator to actuate a starter air valve (SAV) to motor anengine at a predetermined motoring speed.
 2. The method of claim 1,comprising selecting a second pressure valve to provide the duty cycleof pressure to SAV actuator to actuate a starter air valve (SAV) tomotor an engine at a predetermined motoring speed.
 3. The method ofclaim 2, wherein selecting the second pressure valve includes using amanual override (MOR) valve selector.